Thiazolemethine dyes

ABSTRACT

Thiazolemethine dyes of the formula ##STR1## where R 1  and R 2  are each hydrogen, C 1  -C 8  -alkyl with or without substitution, C 3  -C 4  -alkenyl, C 5  -C 7  -cycloalkyl, phenyl or tolyl, or are together with the nitrogen atom joining them together a heterocyclic radical, 
     R 3  is hydrogen, halogen, C 1  -C 8  -alkyl, substituted or unsubstituted phenyl, substituted or unsubstituted benzyl, cyclohexyl, thienyl, hydroxyl or C 1  -C 8  -monoalkylamino, and 
     Q is the radical of an acidic-CH compound, 
     are useful in nonlinear optics.

The present invention relates to novel thiazolemethine dyes of theformula I ##STR2## where R¹ and R² are independently of each otherhydrogen, C₁ -C₈ -alkyl with or without substitution and with or withoutinterruption by one or two oxygen atoms in the ether function, C₃ -C₄-alkenyl, C₅ -C₇ -cycloalkyl, phenyl or tolyl, or are together with thenitrogen atom joining them together a five- or six-membered saturatedheterocyclic radical with or without further hetero atoms,

R³ is hydrogen, halogen, C₁ -C₈ -alkyl, substituted or unsubstitutedphenyl, substituted or unsubstituted benzyl, cyclohexyl, thienyl,hydroxyl or C₁ -C₈ -monoalkylamino, and

Q is the radical of an acidic-CH compound,

and to the use thereof in nonlinear optics.

It is an object of the present invention to provide novel thiazole-basedmethine dyes which shall be advantageous for use in polymeric nonlinearoptical systems. More particularly, such dyes shall possess largehyperpolarizability values, good thermostability, good compatibilitywith the polymers used in nonlinear optical systems, and goodfilm-forming properties with copolymers.

We have found that this object is achieved by the thiazolemethine dyesof the formula I defined at the beginning.

Q in the formula I, being the radical of an acidic-CH compound, can bederived for example from nitromethane, nitroethane or from compounds ofthe formuale IIa to IIh ##STR3## where Y¹ is oxygen or a radical of theformula C(CN)₂,

Y² is oxygen or sulfur,

Y³ is sulfonyl or a radical of the formula C(CN)₂,

X¹ is cyano, nitro, C₁ -C₄ -alkanoyl, substituted or unsubstitutedbenzoyl, C₁ -C₄ -alkylsulfonyl, substituted or unsubstitutedphenylsulfonyl, carboxyl, C₁ -C₄ -alkoxycarbonyl, phenoxycarbonyl,carbamoyl, C₁ -C₄ -mono- or dialkylcarbamoyl, substituted orunsubstituted phenylcarbamoyl or substituted or unsubstituted phenyl,

X² is C₁ -C₆ -alkyl or C₁ -C₆ -alkoxy,

X³ is C₁ -C₄ -alkoxycarbonyl or phenylcarbamoyl,

X⁴ is hydrogen or C₁ -C₆ -alkyl,

X⁵ is cyano, carbamoyl, C₁ -C₄ -alkoxycarbonyl or acetyl,

X⁶ is hydrogen, C₁ -C₈ -alkyl, amino, C₁ -C₆ -mono- or dialkylamino, C₁-C₄ -monoalkanoylamino, benzoylamino or N-(C₁ -C₄-alkanoyl)-N-benzoylamino,

X⁷ is hydrogen, C₁ -C₈ -alkyl, benzyl or phenyl, and

X⁸ is C₁ -C₈ -alkyl.

Any alkyl appearing in the abovementioned formulae can be straight-chainor branched.

Any substituted alkyl appearing in the abovementioned formulae may haveas substituents for example cyano, phenyl, tolyl, hydroxyl, C₁ -C₆-alkanoyloxy, acryloyloxy, methacryloyloxy, C₁ -C₄ -alkoxycarbonyl or C₁-C₄ -alkoxycarbonyloxy with or without substitution by phenyl or C₁ -C₄-alkoxy in the alkoxy group. The number of substituents is generallyfrom 1 to 3, preferably 1 or 2.

Any substituted phenyl appearing in the abovementioned formulae may haveas substituents for example C₁ -C₄ -alkyl, C₁ -C₄ -alkoxy, amino,hydroxyl, halogen or nitro. The number of substituents is generally from1 to 3, preferably 1 or 2.

R¹, R², R³, X², X⁴, X⁶, X⁷ and X⁸ are each for example methyl, ethyl,propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, pentyl,isopentyl, neopentyl, tert-pentyl, hexyl or 2-methyl-pentyl.

R¹, R², R³, X⁶, X⁷ and X⁸ may each also be for example heptyl, octyl,isooctyl or ethylhexyl.

R¹ and R² may each also be for example 2-methoxyethyl, 2- or3-methoxypropyl, 2-ethoxyethyl, 2- or 3-ethoxypropyl, 2-propoxyethyl, 2-or 3-propoxypropyl, 2-butoxyethyl, 2- or 3-butoxypropyl,3,6-dioxaheptyl, 3,6-dioxaoctyl, 2-hydroxyethyl, 2- or 3-hydroxypropyl,2- or 4-hydroxybutyl, 5-hydroxypentyl, 6-hydroxyhexyl, 7-hydroxyheptyl,8-hydroxyoctyl, 2-cyanoethyl, 2- or 3-cyanopropyl, 2-acetyloxyethyl, 2-or 3-acetyloxypropyl, 2-isobutyryloxyethyl, 2- or 3-isobutyryloxypropyl,2-acryloyloxyethyl, 2-methacryloyloxyethyl, 2- or 3-acryloyloxypropyl,2- or 3-methacryloyloxypropyl, 2- or 4-acryloyloxybutyl, 2- or4-methacryloyloxybutyl, 5-acryloyloxypentyl, 5-methacryloxypentyl,6-acryloyloxyhexyl, 6-methacryloyloxyhexyl, 7-acryloyloxyheptyl,7-methacryloyloxyheptyl, 8-acryloyloxyoctyl, 8-methacryloyloxyoctyl,2-methoxycarbonylethyl, 2- or 3-methoxycarbonylpropyl,2-ethoxycarbonylethyl, 2- or 3-ethoxycarbonylpropyl2-methoxycarbonyloxyethyl, 2- or 3-methoxycarbonyloxypropyl,2-ethoxycarbonyloxyethyl, 2- or 3-ethoxycarbonyloxypropyl,2-butoxycarbonyloxyethyl, 2- or 3-butoxycarbonyloxypropyl,2-(2-phenylethoxycarbonyloxy)ethyl, 2- or3-(2-phenylethoxycarbonyloxy)propyl,2-(2--ethoxyethoxycarbonyloxy)ethyl, 2- or3-(2-ethoxyethoxycarbonyloxy)propyl, benzyl, 2-methylbenzyl, 1- or2-phenylethyl, cyclopentyl, cyclohexyl, cycloheptyl, 2-, 3- or4-methylphenyl, allyl or methallyl.

R³ may also be for example fluorine, chlorine, bromine, phenyl,2-methylphenyl, 2,4-dimethylphenyl, 2-methoxyphenyl,2,4-dimethoxyphenyl, benzyl, 2-methylbenzyl, 2,4-dimethylbenzyl,2-methoxybenzyl, 2,4-dimethoxybenzyl, methylamino, ethylamino,propylamino, isopropylamino, butylamino, pentylamino, hexylamino,heptylamino, octylamino or 2-ethylhexylamino.

R¹ and R² combined with the nitrogen atom joining them together into afive- or six-membered saturated heterocyclic radical with or withoutfurther hetero atoms can be for example pyrrolidinyl, piperidinyl,morpholinyl, piperazinyl or N-(C₁ -C₄ -alkyl)piperazinyl.

X¹, X³ and X⁴ are each for example methoxycarbonyl, ethoxycarbonyl,propoxycarbanyl, isopropoxycarbonyl or butoxycarbonyl.

X¹ may also be for example formyl, acetyl, propionyl, butyryl,isobutyryl, benzoyl, 2-, 3- or 4-methylbenzoyl, 2-, 3- or4-methoxybenzoyl, methylsulfonyl, ethylsulfonyl, propylsulfonyl,isopropylsulfonyl, butylsulfonyl, phenylsulfonyl, 2-, 3- or4-methylphenylsulfonyl, 2-, 3- or 4-methoxyphenylsulfonyl, 2-, 3- or4-chlorophenylsulfonyl, mono-or dimethylcarbamoyl, mono- ordiethylcarbamoyl, mono- or dipropylcarbamoyl, mono- ordiisopropylcarbamoyl, mono- or dibutylcarbamoyl,N-methyl-N-ethylcarbamoyl, phenylcarbamoyl, 2-, 3- or4-methylphenylcarbamoyl, 2-, 3- or 4-methoxyphenylcarbamoyl, phenyl, 2-,3- or 4-methylphenyl, 2-, 3- or 4ethylphenyl, 2-, 3- or 4-propylphenyl,2-, 3- or 4-isopropylphenyl, 2-, 3- or 4-butylphenyl,2,4-dimethylphenyl, 2-, 3- or 4-methoxyphenyl, 2-, 3- or 4-ethoxyphenyl,2-, 3- or 4-isobutoxyphenyl, 2,4-dimethoxyphenyl, 2-, 3- or4-chlorophenyl, 2,4-dichlorophenyl, 2-, 3- or 4-nitrophenyl, 2-, 3- or4-hydroxyphenyl or 2-, 3- or 4-aminophenyl.

X² may also be for example methoxy, ethoxy, propoxy, isopropoxy, butoxy,isobutoxy, sec-butoxy, tert-butoxy, pentyloxy, isopentyloxy,neopentyloxy, tert-pentyloxy or hexyloxy.

X⁶ may also be for example mono- or diethylamino, mono- or diethylamino,mono- or dipropylamino, mono- or diisopropylamino, mono- ordibutylamino, mono- or dipentylamino, mono- or dihexylamino,N-methyl-N-ethylamino, formylamino, acetylamino, propionylamino,butyrylamino, isobutyrylamino or N-acetyl-N-benzoylamino.

Preference is given to thiazolemethine dyes of the formula I wherein R¹and R² are independently of each other C₁ -C₆ -alkyl or hydroxyl-,acryloyloxy- or methacryloyloxy-substituted C₂ -C₆ -alkyl.

Preference is further given to thiazolemethine dyes of the formula Iwherein R³ is C₁ -C₆ -alkyl or substituted or unsubstituted phenyl,especially C₁ -C₆ -alkyl, phenyl, hydroxyphenyl or aminophenyl.

Particular preference is given to thiazolemethine dyes of the formula Iwhere R³ is C₁ -C₆ -alkyl or phenyl.

Particular preference is further given to thiazolemethine dyes of theformula I where Q is derived from a compound of the formula IIc, IIe orIIg.

Very particular preference is given to thiazolemethine dyes of theformula I where Q is derived from a compound of the formula IIc, IIe orIIg where Y¹ and Y² are each oxygen, X⁴ is methyl, X⁵ is cyano, X⁶ is C₁-C₆ -alkyl, acetylamino or N-acetyl-N-benzoylamino and X⁷ is C₁ -C₆-alkyl, benzyl or phenyl.

The thiazolemethine dyes of the formula I can be prepared in aconventional manner, for example by condensing an aldehyde of theformula III ##STR4## where R¹, R² and R³ are each as defined above, withan acidic-CH compound of the formula IV

    H.sub.2 Q                                                  (IV),

where Q is as defined above.

The preparation of the aldehydes of the formula III is described forexample in German Patent Application P 44 01 912.2.

The thiazolemethine dyes of the formula I are advantageous for use innonlinear optics.

The compounds of the present invention are thermally stable and haveparticularly large molecular hyperpolarizability values (β₀). The dyesalso possess good compatibility with the polymers used in nonlinearoptical systems and also good film-forming properties in copolymers.

The molecular hyperpolarizability can be determined for example bymeasuring the solvatochromism (see for example Z. Naturforschung 20a(1965), 1441-71, or J. Org. Chem. 54 (1989), 3775-78). This method ofmeasurement involves determining the position of the absorption band ofa compound in different solvents, for example in dioxane or dimethylsulfoxide. The shift of the absorption band is then directlyproportional to the β₀ value, i.e. compounds having a largesolvatochromic shift have a large molecular hyperpolarizability and aretherefore highly suitable for use in nonlinear optical systems (see forexample Chemistry and Industry 1990, 600-608).

Attention may be drawn in particular to the suitability of the novelsubstances for use in communications technology, electro-opticalmodulators (e.g. Mach-Zehnder interferometers), optical switches,frequency mixing or waveguides.

The novel thiazolemethine dyes of the formula I are also advantageouslysuitable for example for dyeing or printing textile materials. These arefor example fibers or fabrics, especially of polyesters, but also ofcellulose esters or polyamides, or blend fabrics of polyesters andcellulose fibers or wool.

The novel thiazolemethine dyes of the formula I are furtheradvantageously suitable for mass coloring polymers, for use inelectrophotography as dyes for electrostatic toners or as thermaltransfer dyes.

The Examples which follow illustrate the invention.

EXAMPLE 1

1.16 g (0.01 mol) of the compound of the formula ##STR5## and 2.32 g(0.01 mol) of N,N'-diphenylbarbituric acid were heated together with0.35 g of sodium acetate and 20 ml of acetic anhydride at 80° C. for 2h. The batch was then cooled down to 20° C. and filtered with suction,and the precipitate was washed with a little methanol and dried at 50°C. under reduced pressure to leave 1.68 g of the compound of the formula##STR6## mp.: 235° C.

EXAMPLE 2

3.9 g (0.01 mol) of the compound of the formula ##STR7## and 1.64 g(0.01 mol) of the compound of the formula ##STR8## were heated togetherwith 0.35 g of sodium acetate and 18 mol of acetic anhydride at 80° C.for 2 h. The precipitate formed on cooling down to 20° C. was filteredoff with suction, washed with a little methanol and dried at 50° C.under reduced pressure to leave 1.65 g of the compound of the formula##STR9## mp.: 220° C. Calculated: C 71.43 H 6.82 N 8.62 Found: C 70.98 H6.78 N 8.44

EXAMPLE 3

3.9 g (0.01 mol) of the compound of the formula ##STR10## and 2.40 g(0.01 mol) of the compound of the formula ##STR11## were heated at 80°C. in 20 ml of acetic anhydride for 2 h. After cooling down, theresulting precipitate was filtered off with suction, washed withmethanol and dried at 50° C. under reduced pressure to leave 2.35 g ofthe compound of the formula ##STR12## mp.: 220° C.

EXAMPLE 4

Example 1 was repeated with the N,N'-diphenylbarbituric acid replaced bythe corresponding amount of N,N'-dibenzylbarbituric acid, affording 0.7g of the compound of the formula ##STR13## mp.: 203° C.

EXAMPLE 5

Example 2 was repeated with the N-methylpyridone replaced by thecorresponding amount of N-hexylpyridone, affording 3.16 g of thecompound of the formula ##STR14## Calculated: C 70.93 H 7.58 N 10.03Found: C 70.60 H 7.50 N 10.10 The same method gives the compounds listedbelow in Table 1.

                                      TABLE 1                                     __________________________________________________________________________    Ex. No.                                                                            Formula                                                                  __________________________________________________________________________          ##STR15##                                                               7                                                                                   ##STR16##                                                               8                                                                                   ##STR17##                                                               9                                                                                   ##STR18##                                                               10                                                                                  ##STR19##                                                               11                                                                                  ##STR20##                                                               12                                                                                  ##STR21##                                                               13                                                                                  ##STR22##                                                               14                                                                                  ##STR23##                                                               15                                                                                  ##STR24##                                                               __________________________________________________________________________

The method described in Z. Naturforschung 20a (1965), 1441-71, wasemployed to measure the absorption maximum of the individual dyes inboth dioxane and dimethyl sulfoxide (DMSO), from which thesolvatochromic shift

Δ_(v) ¹⁸ [cm⁻¹ ] was determined.

The respective results are listed below in Table 2.

                  TABLE 2                                                         ______________________________________                                                 λ.sub.max (dioxane)                                                                   λ.sub.max (DMSO)                                                                  Δ υ                          Ex. No.  [nm]           [nm]       [cm.sup.-1 ]                               ______________________________________                                        1        557            571        440                                        2        576            633        1563                                       3        544            572        900                                        4        544            570        838                                        5        573            634        1679                                       6        573            634        1679                                       7        578            600        634                                        8        537            560        765                                        9        536            541        172                                        ______________________________________                                    

We claim:
 1. A thiazolemethine dye of the formula (I): ##STR25## wherein: R¹ and R² are independently of each other hydrogen, unsubstituted C₁ -C₈ -alkyl, with or without interruption by 1 or 2 oxygen atoms in ether function, C₁ -C₈ -alkyl, with or without interruption by 1 or 2 oxygen atoms in ether function, and which is substituted with cyano, phenyl, tolyl, hydroxyl, C₁ -C₆ alkanoyloxy, acryloyloxy, methacryloyloxy, C₁ -C₄ -alkoxycarbonyl or C₁ -C₄ -alkoxycarbonyloxy with or without substitution by phenyl or C₁ -C₄ -alkoxy in the alkoxy group;C₃ -C₄ -alkenyl, C₃ -C₇ -cycloalkyl, phenyl or tolyl; or are together with a nitrogen atom joining them a 5- or 6-membered saturated heterocyclic radical selected from the group consisting of pyrrolidinyl, piperidinyl, morpholinyl, piperazinyl and N-(C₁ -C₄ -alkyl) piperazinyl; R³ is hydrogen, halogen, C₁ -C₈ -alkyl, phenyl, phenyl substituted by C₁ -C₄ -alkyl, C₁ -C₄ -alkoxy, amino, hydroxyl, halogen or nitro; benzyl; benzyl which phenyl ring thereof is substituted by C₁ -C₄ -alkyl, C₁ -C₄ -alkoxy, amino, hydroxyl, halogen or nitro; cyclohexyl, thienyl, hydroxyl or C₁ -C₈ -monoalkylamino; and Q is a radical of an acidic --CH compound, wherein Q is derived from nitromethane, nitroethane or from compounds of the formulae IIc, IIe or IIf: ##STR26## wherein: Y¹ is oxygen or a radical of the formula --C(CN)₂ ; Y² is oxygen or sulfur; X⁴ is hydrogen or C₁ -C₆ -alkyl; X⁵ is cyano, carbamoyl, C₁ -C₄ -alkoxycarbonyl or acetyl; X⁶ is hydrogen, C₁ -C₆ -alkyl, amino, C₁ -C₆ -mono- or dialkylamino, C₁ -C₄ -monoalkanoylamino, benzoylamino or N-(C₁ -C₄ -alkanoyl) -N-benzoylamino; X⁷ is hydrogen, C₁ -C₆ -alkyl, benzyl or phenyl; and X⁸ is C₁ -C₈ alkyl.
 2. The thiazolemethine dye of claim 1, wherein R¹ and R² are independently of each other C₁ -C₆ -alkyl or hydroxyl-, acryloyloxy- or methacryloyloxy-substituted C₂ -C₆ -alkyl.
 3. The thiazolemethine dye of claim 1 wherein R³ is C₁ -C₆ -alkyl phenyl or phenyl substituted with C₁ -C₄ -alkyl, C₁ -C₄ alkoxy, amino, hydroxyl, halogen or nitro.
 4. The thiazolemethine dye of claim 1, wherein R³ is C₁ -C₆ -alkyl, phenyl, hydroxyphenyl or aminophenyl.
 5. The thiazolemethine dye of claim 1, wherein Q is radical IIc.
 6. The thiazolemethine dye of claim 1, wherein Q is radical IIe.
 7. The thiazolemethine dye of claim 1, wherein Q is radical IIf.
 8. The thiazolemethine dye of claim 1, wherein Q is radical IIc or IIe; Y¹ and Y² are each oxygen; X⁴ is methyl; X⁵ is cyano; X⁶ is C₁ -C₆ -alkyl, acetylamino or N-acetyl-N-benzoylamino; and X⁷ is C₁ -C₆ -alkyl, benzyl or phenyl. 